Nobody has put up any walls yet

. All that's happened so far on that front is Hal
planning to put up walls.
Besides, even if the walls were up, it's not unheard of at all for constructs made with power rings to be broken. Superman has broken them plenty of times before with raw brute strength, and currently the Parasite has the strength of J'onn J'onzz (near equal to Superman), Blackrock (equal to Superman), Neutron (near equal to Superman), a zillion Riots (each of them have a small amount of superstrength), some GL power, and some of Superman's power.
In fact, I'd be completely surprised if Rudy
didn't break a GL construct if he went up against one right now.